This instrumentation application requests funds to purchase a liquid chromatography (LC)/mass spectrometry (MS) system comprised of a Thermo Altis triple stage quadrupole (TSQ) mass spectrometer, Vanquish LC and autosampler, and workstation computer. The proposed instrumentation will be housed at the Saint Louis University Department of Biochemistry and Molecular Biology Lipidomics Core Facility. This instrumentation is needed to enhance and maintain lipidomics service to a large Major Users group that has relied on a Quantum TSQ system purchased in 2004 with funds provided by an NIH S10 award (S10RR019232), which has provided continuous service for 13 years to NIH-funded investigators. The proposed instrumentation is also needed since the currently used Thermo Quantum mass spectrometer is a discontinued TSQ model last sold by Thermo in 2013 and support and parts for the Quantum may not be available in the near future. Purchasing the Altis TSQ/Vanquish LC system will enable the Major Users group at Saint Louis University to continue their studies into the next decade without interruption. The Altis TSQ/Vanquish LC system is needed for identification and characterization of new lipid molecules as well as quantitation of lipids and lipid metabolites. The Altis TSQ/Vanquish LC also has greater sensitivity compared to older models (e.g., the Quantum). This improved sensitivity will be invaluable for many of the proposed Major Users. The increased sensitivity will improve many LC/MS analyses since a number of the proposed users have interests in measuring low abundance oxidized lipid species and bioactive lipid metabolites that are: 1) mediators of disease; 2) biomarkers of human disease; and 3) products from novel lipidomic screening assays. The Altis TSQ mass spectrometer and Vanquish LC instrument system is essential for the LC/MS and shotgun lipidomic studies at Saint Louis University's School of Medicine. The Lipidomics Core Facility is directed by the PI of this application, Dr. Ford, and is supervised by a full time employee, Carolyn Albert, who has worked in this facility for over 13 years. The facility has been involved in employing both shotgun lipidomics techniques for users as well as the development of LC/MS analyses of new molecules discovered by Major Users. This facility has provided services to both investigators at Saint Louis University as well as many outside users. Members of the Saint Louis University Major Users Group have appointments in four different departments at the School of Medicine. The eight Major Users are involved in translational and basic research in the fields of cardiovascular disease, sepsis, cancer, liver disease, diabetes, immunology, and obesity. Ongoing lipidomic studies at Saint Louis University have provided a focal point for collaborations for many NIH-funded investigators (including the proposed users) in both clinical and basic science departments. The proposed instrumentation has strong support from the Institution including support for both future service contracts and potential budgetary needs to maintain optimal performance of the Altis TSQ/Vanquish LC system for the Major and Minor users.